The present invention relates to a skid prevention method and an anti-skid brake device for embodying the method in which brake devices of wheels may be controlled by control devices provided with main control systems and an auxiliary control system adapted to be actuated when main control systems fail.
A vehicular anti-skid brake device is such that when a possibility of a lock of a wheel occurs as a result of an excessive braking input based on the braking operation of a driver, the braking device is controlled so as to decrease the braking torque irrespective of the braking input based on the braking operation of the driver to thereby prevent the lock of the wheel and secure the directional stability and steerability of the vehicle, and in addition, shorten the braking distance, offering an action which can enhance the safety of the vehicle.
However, since the anti-skid brake device is a device which controls the braking torque of wheels irrespective of the braking input based on the braking operation of the driver, when a failure occurs with the anti-skid brake device being in operation, there is a possibility of fully ineffective braking, and in the event the anti-skid brake device becomes entirely inoperative as a result of a failure thereof, it is likely to cause the wheels to be locked by the braking operation of the driver who places full confidence in the anti-skid brake device. In either case, it is very dangerous.
Generally, it is possible, when the anti-skid brake device has failed, to give a driver an alarm about the failure and to secure the normal braking function of the braking device. However, in the event the anti-skid brake device has failed immediately before the braking or during the braking, it is hardly possible for the driver to cope therewith quickly and adequately even if such an alarm should be given to him, and the vehicle will lose its directional stability to get into danger, resulting in a serious accident. Moreover, there has not been a method or apparatus for sufficiently preventing such a dangerous situation.